The present study is designed to elucidate the effects of tryptophan depletion on mood and alcohol craving in remitted depressives with concomitant alcohol dependence. The study will compare the central serotonergic function between groups of depressed, alcoholic subjects who sustained an antidepressant response to either sertraline or placebo. In addition, serotonergic function will be related to primary/secondary depression classification and current alcohol drinking status.